Spin glass phase transition in Hg1−kMnkTe semimagnetic semiconductors

Low field interband Faraday rotation and a.c. magnetic susceptibility are investigated in Hg_1?kMn_kTe and Hg_1?k?xMn_kTe semimagnetic semiconductors (k?0.5). The spin glass phase transition is experimentally manifested by characteristic cusps in χ(T) and kinks in θ(T). The transition temperatures obtained from both types of experiments are well correlated which enable us to determine the phase diagram for Hg_1?kMn_kTe system. The spin glass phase transition occurs at low temperature in quaternary alloys than in Hg_1?kMn_kTe alloys with identical Mn composition. This implies that the antiferromagnetic interaction between Mn²⁺ ions due to the virtual valence to conduction band transitions plays a significant role in the mechanism responsible for the spin glass formation.